NIE question

Hello all,

I have a little problem to solve: In 2008 my wife and I obtained our NIE s. They are of this format: X-01234567-A, the first digit is a 0. When I tried this NIE in form 210 ( Renta de no residentes) it did not  work, however when I removed the 0, it worked as X1234567A.  So since then I have prepared my tax forms every year , also registered for IBI and others with the truncated version. So the question is: What is my real NIE number, if the official one does not work in forms? For example for a notary to indicate my identity on an Escritura de Compraventa, which one would or should he use?

It's a letter X then 7 numbers and another letter. So your format without the 0 is correct.

It works the same on my SIP card where I have to leave the 0 off at the beginning.

Thank you mariedav. So it seems I am not in an uncommon situation.